The present invention relates to refiners for wood pulp or the like, and more particularly to improvements in refiners wherein stationary refining plates flank rotary refining plates in the chamber of a housing whose inlet admits stock for treatment by comminuting projections (e.g., ribs) on the neighboring surfaces of stationary refining plates and rotary refining plates.
It is already known to utilize in a disc or rotor refiner two coaxial or eccentric plates or discs each of which is driven by a discrete prime mover and which have neighboring surfaces provided with ribs or otherwise configured projections which comminute the material to be treated while the material advances from the inlet toward the outlet of the stock chamber.
It is further known to use a pair of discs one of which is stationary and the other of which rotates relative to the stationary disc.
It is also known to dispose two rotary discs between two stationary discs so that each rotary disc cooperates with a different stationary disc. The rotary discs are mounted at the opposite sides of a disc-shaped carrier which is driven by a shaft. The stock is fed through one of the stationary discs to enter the space between the one stationary disc and the respective rotary disc, and some of the stock is allowed to pass through relatively small openings in the rotary discs to enter the space between the other rotary disc and the other stationary disc.